Such installations are used, according to WO 98/40531, for example, to introduce plastic bottles, such as PET bottles, into a treatment room, where they are coated to improve the barrier properties. In order to maintain control over the container during the introduction, during the passage through the lock rotor and during the removal, and, to always keep the container in a correct position (including for the protection of the container surface), and for reasons pertaining to process reliability, clamps are used which work in cooperation. Process reliability is an extremely important factor, because a disturbance resulting from a bottle which has assumed an incorrect position or has become released, requires the stoppage of the operation of the installation, the breaking of the low pressure, and the switching off of the installations in the treatment room, and it requires a longer stoppage time which means high costs. In some cases, all the containers have to be removed from the treatment room, before the installation and the treatment station can be started again. Although the use of the clamps should already result in a relatively high process reliability, one can not avoid, precisely in the case of a lock rotor having, for example, more than twenty lock chambers, that the process of the transfer of a container from a star wheel to the lock rotor or from the lock rotor to a star wheel does not succeed, and one container remains in a lock chamber, which must be empty for the introduction of a new container. In that case, a disturbance in the course of operation cannot be avoided.
Furthermore, from U.S. Pat. No. 1,766,018 it is known, in the case of a lock rotor pair each having only six lock chambers for containers that are to be closed in a vacuum, to provide a ram which is arranged diametrically in each/lock rotor. Each ram engages, with its ends, into diametrically opposite lock chambers, and it is actuated in such a manner (by the vacuum, an entering container, or a drive), that it pushes a container to be transferred out of the lock chamber. If, under unfavorable circumstances, the container to be pushed out remains in its lock chamber, an exceedingly difficult to correct disturbance occurs, which causes damages, because there is no possibility to remove the container which remained in position in an unscheduled manner.
The invention is based on the task of producing an installation of the above-mentioned type, where operating disturbances caused by containers which remain in position in an unscheduled manner can be reliably avoided.
The core of the invention consists in incorporating, in spite of the xe2x80x9creliablexe2x80x9d controlled transfer and the continuous positioning of the container by the gripping and holding devices, an additional device in the installation, which removes the container from the lock chamber, in the theoretically unlikely case, which in practice can, however, not be ruled out, namely where a container remains in an unscheduled manner in a lock chamber; this occurs, in particular, in cooperation with the discharge area which is provided on purpose, so that it is not only possible to remove every remaining container from the lock rotor, it also feasible to do this in such a manner that no further operating disturbances can be caused. The multiple safety features in the container conveyance considerably increase the process reliability, in cooperation with the internal and external discharge areas; moreover, this goal is achieved at justifiable construction costs.
In principle, two variants are advantageous here. The ejection element is either positioned outside of the lock rotor and close to the discharge area, and it is introduced from the outside into the lock chamber for insertion, or the ejection element is placed inside, in the lock rotor, and it is adjusted from inside into the position of ejection into the lock chamber. In the first case, only one ejection element at least is required in each discharge area. In the second case, at least one ejection element is required for each lock chamber.
Advantageously, the ejection element with an adjustment device is arranged, separately from the star wheels of the pair and the lock rotor, in the discharge area, in such a manner that no collisions with these components of the installation can occur.
Alternately, an ejection element, which is secured in an adjustable position in the lock rotor, is provided in the lock rotor for each lock chamber. To activate the ejection element, two construction variants are advantageous. If each ejection element is associated with its own adjustment device which follows the lock rotor, the construction costs are higher, however, the control technological costs may be lower. In the other case, each discharge area is associated with only one adjustment device which is assigned jointly to all the ejection elements. In this case, the construction costs are lower.
An alternate embodiment which is easy to construct, safe in its operation and takes little space, uses rams which are associated with the lock chambers, and which are maintained by spring force in the rest position, and then adjusted into the ejection position, once they have reached a discharge area.
Advantageously, each ram is guided in a guide in the lock rotor, which allows linear adjustment, where the guide should be designed so it provides a pressure seal in view of the fact that in the treatment room the pressure is higher or lower than atmospheric pressure.
In a simple alternate embodiment, each adjustment device consists of a curved track which is in stationary position, and which is directed to the given discharge area, and in which the rams arrive in succession, and are adjusted into their ejection positions. The spring force is responsible for returning the ram to its original position. To prevent wear, the rams can be equipped with rollers, balls or glide cushions.
A particularly advantageous alternate embodiment has an adjustment device, which is in a working connection with a sensor, which activates the adjustment device if a container remained in position in an unscheduled manner, and the adjustment device conveys, by means of the ram, the container into the discharge area. For this purpose, an actuator is used, advantageously a pneumatic cylinder, which is controlled by a magnetic valve, and which adjusts the ram, either directly, or preferably over a movable curved track, into the ejection position.
Because the lock rotor rotates at considerable speed, it is advantageous to place the sensor outside of the lock rotor and before, or at the beginning of, the discharge area. To avoid the need for a disadvantageous modification of the design of the lock rotor, it is advantageous to attach the adjust device to a stationary foundation plate.
In a simple alternative, the ejection element is a following swivel secured lever, which is adjusted into the ejection position by means of stationary curved tracks or cam surfaces.
To prevent containers, which remained in position in an unscheduled manner and which were ejected to prevent damage, from causing subsequent damage, it is advantageous to provide a container collection device or a sorting device in each discharge area.
Advantageously, each ejection element is arranged under the gripping and holding devices, specifically at a height which guarantees a rapid and reliable ejection.
To allow sufficient time, even in the case of a rapidly rotating lock rotor, for the ejection of a container which remained in place in an unscheduled manner, it is advantageous to separate the star wheels of each pair in the circumferential direction of the lock rotor more than is conventionally done under normal conditions.